The debate about how to best handle head injuries in soccer became more inflamed during this summer’s World Cup, when fans witnessed incidents in which players clearly sustained serious blows to the head yet quickly returned to the field. Now, with the top domestic leagues in Europe set to begin their seasons, England’s Premier League has announced changes to its in-game injury protocols.

Effective immediately, the Premier League will require that any player who has a “confirmed or suspected period of loss of consciousness” on the field must be removed from the game and forbidden to return. More important, the league is mandating that a team’s doctor — not coaches or the player himself —will be empowered to determine whether the player was knocked out and, if he was not, whether he is fit to continue.

Clubs will also be required to perform baseline cognitive testing on players before each season. Alecko Eskandarian, the top draft pick in M.L.S. in 2003, led D.C. United to a title in ‘04, but later was forced to retire because of multiple head injuries.

Video replay to be used

Critics will note that even with the new regulations, it is still a team employee, the doctor, deciding whether a player can keep playing. But the new rules require that Premier League clubs have a third doctor present at every game who will be stationed in the tunnel between the locker room and the field. That doctor will monitor play and use video replay to help identify players who may have sustained head injuries.

The so-called tunnel doctor will have a significant role in identifying when players have lost consciousness, though the doctor will still be paid by the home club, not the league.

“My biggest concern right when I saw the announcement was there not being a neutral doctor making the decisions, because you still have the conflict of interest when a doctor being paid by a team makes personnel decisions,” said Taylor Twellman, a former United States national team player whose career was cut short by the effects of concussions. Twellman has become an outspoken advocate for overhauling the treatment of players who sustain head injuries.

Twellman added that it would be difficult for team physicians not to feel pressure from fans or other team members when evaluating a star player in an important game. “What happens if a team doctor is overcautious?” he said. “You know there will still be pressure on doctors to keep the best players in” the game.

In a sport that is notoriously slow to change, the Premier League’s modifications are an improvement on past practices. Last season, the league was harshly criticized after an incident involving Tottenham goalkeeper Hugo Lloris, who clearly lost consciousness after a violent collision with an opposing player in a league game against Everton. During the World Cup, there were at least three incidents in which players appeared to sustain serious head injuries but continued playing. The most notable came during the group stage, when Uruguay’s Álvaro Pereira crumpled to the ground after colliding with Raheem Sterling of England.

Pereira was obviously unconscious – several players motioned frantically for trainers to hurry onto the field and help – and it seemed inevitable that he would be substituted. But after being revived, and after Uruguay’s team doctor had signaled for a substitute to get ready, Pereira argued with team officials and persuaded them to let him in the game. (Uruguay won, 2-1.)

Similarly, Germany’s Christoph Kramer lost consciousness early in the World Cup final against Argentina but returned to the field before being substituted about 10 minutes later. It was later revealed that Kramer was so dazed that during play, he asked the referee whether the game going on around him was in fact the tournament’s final match.